To　solve　the　problem　of　arc　suppression　under　the　single-phase　grounding　fault　in　distribution　network,　a　novel　approach　based　on　cascaded　H-bridge　converters　and　dq　reference　frame　transformation　is　proposed.　A　flexible　grounding　mode　using　three-phase　cascaded　H-bridge　converter　is　firstly　adopted　in　network.　The　current　injected　in　non-fault　phases　can　compensate　the　arc　current　at　fault　point　and　suppress　the　recovery　voltage　of　fault　phase.　It　could　promote　the　rapid　extinguishment　of　arc　and　make　it　restrike　hardly.　Then　combined　with　the　features　of　cascaded　H-bridge　converter,　a　new　detecting　method　for　harmonic　and　transient　components　of　fault　current　based　on　dq　reference　frame　transformation　has　been　proposed.　This　method　can　realize　the　full　current　compensation　in　the　cases　of　both　stable　and　intermittent　arc　grounding　faults.　According　to　the　mechanisms　of　current　injected　by　cascaded　H-bridge　converter　on　fault　current　and　fault　phase　recovery　voltage,　a　unified　arc　suppression　method　about　various　arc　grounding　faults　has　been　studied.　Simulation　results　show　the　proposed　approach　is　effective,　which　can　improve　arc　extinguishment　rate,　promote　the　study　and　application　of　FACTS　technique　in　grounding　fault　protection　of　smart　power　distribution　network.　©　2016,　The　editorial　office　of　Transaction　of　China　Electrotechnical　Society.　All　right　reserved.